Rotary union seals can involve double standard mechanical seal assemblies that process fluids, typically oil, injected between the two seals. Rotary union seals may, for example, be used in applications involving hollow engine shafts. Fluid, such as oil, may be transferred from a casing of an engine (stationary component) via hollow shafts (rotating component). The fluid may then exit at different positions associated with the shaft. Feeding fluids like oil in a rotating shaft with holes can involve functional challenges, including centrifugal forces and sloshing.
With double-seal assemblies, two seals may be mounted back-to-back, for example, in a north-south configuration. Double-seal assemblies may be complex, can result in a significant weight increase, and may be cumbersome for certain applications. In many instances, such double-seal assemblies may be small in size, e.g., less than six inches in diameter. However, on a comparative basis, such double-seal assemblies may consume a considerable amount of axial space as the diameter increases and they may be limited in axial and radial extents.
Among other things, it can be a challenge to provide efficient axial and radial sealing assemblies, including one that may involve a single seal, while seeking compact, simplified, and efficient designs. Moreover, it can be a challenge to provide improved seals for diameters exceeding six inches, utilizing reduced axial space.